package com.hmdp.service.impl;

import ch.qos.logback.classic.spi.EventArgUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.RedisData;
import com.hmdp.utils.SystemConstants;
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.geo.Point;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;

import java.time.LocalDateTime;
import java.util.*;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import static com.hmdp.dto.Result.fail;
import static com.hmdp.dto.Result.ok;
import static com.hmdp.utils.RedisConstants.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;


    @Resource
    private CacheClient cacheClient;
    @Override
    public Result queryById(Long id) {
        //缓存穿透
//        Shop shop  = cacheClient
//                .queryWithPassThrough(CACHE_SHOP_KEY,id,Shop.class,this::getById,CACHE_SHOP_TTL,TimeUnit.MINUTES);

//        互斥锁解决缓存击穿
   //     Shop shop = queryWithMutex(id);
        Shop shop = cacheClient.queryWithLogicalExpire(CACHE_SHOP_KEY,id,Shop.class,this::getById,20L,TimeUnit.SECONDS);
        if(shop == null){
        return Result.fail("店铺不存在!");
        }
//        //用逻辑过期来解决

        //返回
        return Result.ok(shop);
    }

    private static  final ExecutorService CACHE_REBUILD_EXECUTOR = Executors.newFixedThreadPool(10);
//    public Shop queryWithLogicalExpire(Long id){
//        String key = CACHE_SHOP_KEY + id;
//        //1、从redis查询商品的缓存
//        String shopJson = stringRedisTemplate.opsForValue().get(key);
//        //2、判断缓存是否存在
//        if (StrUtil.isBlank(shopJson)){
//            //3、缓存存在，直接返回
//            return null;
//        }
//        //4、命中，先把json反序列化为对象
//        RedisData redisData = JSONUtil.toBean(shopJson, RedisData.class);
//        Shop shop = JSONUtil.toBean((JSONObject) redisData.getData(), Shop.class);
//        LocalDateTime expireTime = redisData.getExpireTime();
//        //5、判断是否过期
//        if (expireTime.isAfter(LocalDateTime.now())){
//            //5.1 未过期 直接返回店铺信息
//            return shop;
//        }
//        //5.2 已过期缓存重建
//        //6、 缓存重建
//        //6.1 获取互斥锁
//        String lockKey = LOCK_SHOP_KEY + id;
//        boolean isLock = tryLock(lockKey);
//        //6.2 判断获取锁成功
//        if(isLock){
//            //6.3 成功 开启独立线程 实现缓存重建 创建了线池
//            CACHE_REBUILD_EXECUTOR.submit(() -> {
//                try {
//                    //重建缓存
//                    this.saveShop2Redis(id,20L);
//                } catch (Exception e) {
//                    throw new RuntimeException(e);
//                }finally {
//                    //释放锁
//                    unLock(lockKey);
//                }
//
//            });
//        }
//
//
//        //6.4 返回商铺信息
//
//        return shop;
//    }
    public Shop queryWithMutex(Long id){
        String key = CACHE_SHOP_KEY + id;
        //1、从redis查询商品的缓存
        String shopJson = stringRedisTemplate.opsForValue().get(key);

        //2、判断缓存是否存在
        if (StrUtil.isNotBlank(shopJson)){
            //3、缓存存在，直接返回
            Shop shop = JSONUtil.toBean(shopJson, Shop.class);
            return shop;
        }
        //判断命中是否为空值
        if (shopJson != null){
            return null;
        }
        //4、实现缓存重建
        //4.1 获取互斥锁
        String lockKey = LOCK_SHOP_KEY + id;
        Shop shop = null;
        try {
            boolean isLock = tryLock(key);
            //4.2 判断是否获取锁成功
            if(!isLock){
                //4.3 失败则休眠重试
                Thread.sleep(50);
                queryWithMutex(id);
            }
            //4.4成功，根据id查询数据库
            shop = getById(id);
            //模拟重建时的延时
            Thread.sleep(200);
            //5、数据库不存在，返回错误
            if(shop == null){
                //将空值写入数据库
                stringRedisTemplate.opsForValue().set(key, "",CACHE_NULL_TTL, TimeUnit.MINUTES);
                return null;
            }
            //6、数据库存在，写入redis
            stringRedisTemplate.opsForValue().set(key, JSONUtil.toJsonStr(shop),CACHE_SHOP_TTL, TimeUnit.MINUTES);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }finally {
            //7、释放锁
            unLock(lockKey);
        }

        //8、返回数据
        return shop;
    }
//    public Shop queryWithPassThrough(Long id){
//        String key = CACHE_SHOP_KEY + id;
//        //1、从redis查询商品的缓存
//        String shopJson = stringRedisTemplate.opsForValue().get("Cache:shop:" + id);
//
//        //2、判断缓存是否存在
//        if (StrUtil.isNotBlank(shopJson)){
//            //3、缓存存在，直接返回
//            Shop shop = JSONUtil.toBean(shopJson, Shop.class);
//            return shop;
//        }
//
//        if (shopJson != null){
//            return null;
//        }
//        //4、缓存不存在，查询数据库
//        Shop shop = getById(id);
//        //5、数据库不存在，返回错误
//        if(shop == null){
//            //将空值写入数据库
//            stringRedisTemplate.opsForValue().set(key, "",CACHE_NULL_TTL, TimeUnit.MINUTES);
//            return null;
//        }
//        //6、数据库存在，写入redis
//        stringRedisTemplate.opsForValue().set(key, JSONUtil.toJsonStr(shop),CACHE_SHOP_TTL, TimeUnit.MINUTES);
//
//        //7、返回数据
//        return shop;
//    }
    private boolean tryLock(String key){
        Boolean flag = stringRedisTemplate.opsForValue().setIfAbsent(key, "1", 10, TimeUnit.MINUTES);
        return BooleanUtil.isTrue(flag);
    }
    private void unLock(String key){
        stringRedisTemplate.delete(key);
    }

    public void saveShop2Redis(Long id,Long expireSeconds) throws InterruptedException {
        //1、查询店铺数据
        Shop shop = getById(id);
        //2、封装逻辑过期时间
        RedisData redisData = new RedisData();
        redisData.setData(shop);
        redisData.setExpireTime(LocalDateTime.now().plusSeconds(expireSeconds));
        //3、写入redis
        stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY + id, JSONUtil.toJsonStr(redisData));
    }
    @Override
    //加事务
    @Transactional
    public Result update(Shop shop) {
        Long id = shop.getId();
        if(id == null){
            return fail("店铺id不能为空");
        }
        //1、先更新数据库信息
        updateById(shop);
        //2、删除redis缓存
        stringRedisTemplate.delete(CACHE_SHOP_KEY + shop.getId());
        return null;
    }

    @Override
    public Result quryShopByType(Integer typeId, Integer current, Double x, Double y) {
        //1、判断是否需要根据坐标查询
        if(x==null||y==null){
            //不需要坐标查询，按数据库查询
            Page<Shop> page = query()
                    .eq("type_id", typeId)
                    .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
            //返回数据
            return Result.ok(page.getRecords());
        }
        //2、计算分页参数
        int from = (current-1)*SystemConstants.DEFAULT_PAGE_SIZE;
        int end = current*SystemConstants.DEFAULT_PAGE_SIZE;
        //3、查询redis。按照距离排序分页 结果 shopId、distance
        String key = SHOP_GEO_KEY + typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> result = stringRedisTemplate.opsForGeo()
                .search(
                        key,
                        GeoReference.fromCoordinate(x, y),
                        new Distance(5000),
                        RedisGeoCommands.GeoSearchCommandArgs.newGeoSearchArgs().includeCoordinates().limit(end)
                );
        //4、解析出id
        if(result == null) {return Result.ok(Collections.emptyList());}
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> list = result.getContent();
        //4.1截取from 到end的部分
        List<Long> ids = new ArrayList<>(list().size());
        Map<String,Distance> distanceMap = new HashMap<>(list.size());
        list.stream().skip(from).forEach(result1 -> {
            //4.2获取店铺id
            String shopIdStr =result1.getContent().getName() ;
            System.out.println("ids"+shopIdStr);
            ids.add(Long.valueOf(shopIdStr));
            //4.3获取店铺距离
            Distance distance = result1.getDistance();
            distanceMap.put(shopIdStr,distance);
        });
        //5、根据id查询店铺
        String idStr = StrUtil.join(",",ids);
        if (ids.isEmpty()) {
            return Result.ok(Collections.emptyList());
        }
        List<Shop> shops = query().in("id", ids)
                .last("order by field (id,"+idStr+")")
                .list();
        for (Shop shop : shops) {
            shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
        }

        return Result.ok(shops);
    }
}
